Surya Henna Cream / Great distress and pain over several days

I have a severe ppd allergy, i emailed the company about its products as it says there are ppd free and use no chemicals, only natural plants and herbs in their hair colours. They told me i would be safe to use them, and i did since ive used them i have had a bad reaction and have had an itchy head open sores and swelling of the neck due to there product. I have email them again and they said there natural product may contain some disperse dyes (no mention of this in the instructions or on the box otherwise i would not of used it) this reaction has caused me great distress and pain over several days and i have had to take antihistamines to reduce the swelling.